Image processing apparatus and method

ABSTRACT

An image processing apparatus inputs captured image data that has been read from an image capturing unit in accordance with a reading mode, and processes the input captured image data so as to enable identification of the reading mode used in reading the captured image data from the image capturing unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing apparatus andmethod for processing captured image data read from an image capturingunit.

2. Description of the Related Art

Some of the recent image capturing elements can switch among “all-pixelreading mode”, “partial reading mode”, and “thinned-out reading mode”.In the “all-pixel reading mode”, signals are read from all of the pixelson an image capturing element. In the “partial reading mode”, signalsare read only from pixels located in an arbitrary region on the imagecapturing element. In the “thinned-out reading mode”, signals are readwhile skipping pixels on the image capturing element at an arbitraryinterval. The “partial reading mode” and the “thinned-out reading mode”may be combined, that is to say, signals may be read while skippingpixels located in an arbitrary region at an arbitrary interval.

Conventionally, there has been a surveillance camera systemincorporating an image capturing element that can change its readingmode.

US 2009/0160947 A1, granted a patent, discloses a system for reading adesignated region on an image capturing element at a short timeinterval, and performing thinned-out reading of other regions inmultiple batches at a longer time interval. US 2009/0160947 A1 alsodiscloses a system in which an entire-region thinned-out image isdisplayed on the left side of a monitor, and a partial image isdisplayed on the right side of the monitor in an enlarged manner.

Furthermore, an image capturing system is configurable that continuouslyreads only a specific region but does not read regions other than thespecific region.

However, the image capturing system disclosed in US 2009/0160947 A1 doesnot explicitly display the frequencies at which entire-regionthinned-out images and partial images are read. This poses the problemthat the frequencies at which the entire-region thinned-out images andpartial images are updated cannot be visually perceived. In addition,the skip interval for image reading cannot be visually perceived.

Similarly, in the case where only a specific region is continuously readand regions other than the specific regions are not read, it is notpossible to visually perceive how long the regions other than thespecific region have been left without being updated.

SUMMARY OF THE INVENTION

The present invention provides an image processing apparatus forprocessing captured image data that has been read from an imagecapturing unit, the apparatus including: an input unit that inputscaptured image data read from the image capturing unit in accordancewith a reading mode; and a processing unit that processes the capturedimage data input by the input unit so as to enable identification of thereading mode used in reading the captured image data from the imagecapturing unit.

The present invention also provides an image processing method used inan image processing apparatus for processing captured image data thathas been read from an image capturing unit, the method including thesteps of: inputting captured image data that has been read from theimage capturing unit in accordance with a reading mode; and processingthe input captured image data so as to enable identification of thereading mode used in reading the captured image data from the imagecapturing unit.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one working example of a configuration of an imageprocessing apparatus.

FIG. 2 shows an example of display on an image display unit.

FIG. 3 shows an example of a user interface for setting an imagecapturing instruction parameter.

FIG. 4 shows an example of an image capturing instruction parameter.

FIG. 5 is a flowchart of a procedure of an image processing unit.

FIGS. 6A and 6B show one example of a relationship between a readingfrequency and the intensity of the effect of image processing, and anexample of image processing executed in accordance with the readingfrequency.

FIGS. 7A and 7B show one example of a relationship between a post-pixelupdate elapsed period and the intensity of the effect of imageprocessing, and an example of image processing executed in accordancewith the post-pixel update elapsed period.

FIGS. 8A and 8B show one example of a relationship between a skipinterval and the intensity of the effect of image processing, and anexample of image processing executed in accordance with the skipinterval.

DESCRIPTION OF THE EMBODIMENT

The present invention will be described below in detail based on anembodiment with reference to the attached drawings. It should be notedthat configurations presented in the following embodiment are merelyillustrative, and the present invention is by no means limited toconfigurations shown in the drawings.

FIG. 1 shows one example of a configuration of an image processingapparatus.

In FIG. 1, the image processing apparatus is made up of an imageacquisition apparatus 100 and an image display apparatus 150. The imageacquisition apparatus 100 is composed of an image capturing control unit101, an image capturing unit 102, and an image transmission unit 103.The image display apparatus 150 is composed of a setting unit 151, animage reception unit 152, an image processing unit 153, a storage unit154, and an image display unit 155.

The setting unit 151 sets an image capturing instruction parameter inaccordance with the result of a user operation on an input interface(I/F) 160, such as a mouse. The image capturing instruction parameter isa parameter related to an image capturing method used by the imagecapturing unit 102. For example, the image capturing instructionparameter includes at least one of a region on an image capturingelement, a skip interval for pixels on the image capturing element, anda reading frequency for the image capturing element. The region on theimage capturing element has, for example, a rectangular shape or anypolygonal shape. Alternatively, the region may have any other shape. Thenumber of the region is one or more. The reading frequency denotes thenumber of times an image is read from the image capturing element withina certain time period. The skip interval denotes a rate at which readingof pixels is skipped. A method for setting the image capturinginstruction parameter will be described later.

The image capturing control unit 101 receives the image capturinginstruction parameter set by the setting unit 151, and controls an imagecapturing method (image acquisition method) used by the image capturingunit 102.

Based on the image capturing instruction parameter set by the imagecapturing control unit 101, the image capturing unit 102 acquiressignals corresponding to light focused on the image capturing element.Then, an image is formed by applying, to the acquired signals,processing such as AD conversion in accordance with a method set by aprogram and the like. The image capturing unit 102 can not only set aplurality of reading regions, but also perform at least one of changingof the reading regions and acquisition control for the reading regions.The acquisition control mentioned herein denotes, for example, controlof the reading frequency or the skip interval for images. However, theacquisition control is not limited to such control, and may be, forexample, control of a bit depth of the image capturing elements andcontrol of the number of bands of the image capturing element.

The image transmission unit 103 receives the image, an image capturingexecution parameter used to form the image, and an image generation timefrom the image capturing unit 102, and transmits them to the imagereception unit 152. The items included in the image capturing executionparameter are similar to those included in the image capturinginstruction parameter. However, due to hardware-related restrictions onthe image capturing element, the values of the image capturing executionparameter do not necessarily match those of the image capturinginstruction parameter. The transmitted image may be a sequence ofcontinuous still images such as JPEG images, or may be a video generatedfrom a sequence of continuous still images using MPEG and the like.

The image reception unit 152 receives the image, the image capturingexecution parameter, and the image generation time from the imagetransmission unit 103, and passes them to the image processing unit 153.

The image processing unit 153 receives the image, the image capturingexecution parameter, and the image generation time from the imagereception unit 152. With the use of the received information, an imageis generated by updating a part or an entirety of an image stored in thestorage unit 154. Furthermore, processing for enabling visualdistinction is executed in accordance with the reading frequency forimage reading, the skip interval for image reading, or a time periodthat has elapsed since the last image update. A detailed descriptionwill be given later.

The storage unit 154 stores an image that has been stored by the imageprocessing unit 153 in the past, together with pixel update timeinformation. The pixel update time information shows the imagegeneration time of an image for which pixels were last updated. Thepixel update time information holds image update times of all pixels.For example, assume the case where an entire image has been updated insequence using three images with the image generation times of 0, 100and 200. In this case, if only pixels of a certain region are updated insequence using three images with the image generation times of 210, 220and 230, the image update times of the pixels belonging to the certainregion are 230, and the image update times of pixels belonging to otherregions are 200.

The image display unit 155 displays the image generated by the imageprocessing unit 153 on an external apparatus such as a display. Below,it will be assumed that the image capturing element operates in anall-pixel reading mode (first reading mode) at first and then changes toa partial reading mode (second reading mode) as it progresses, and adescription will be given of an image that is displayed when ten secondshas elapsed since the change. FIG. 2 shows an image 200 displayed by theimage display unit 155 in this case.

An entire image display part 201 displays an image of the same angle ofview as a region captured when the image capturing element performsall-pixel reading. In this case, an image that was last acquired tenseconds ago in the all-pixel reading mode is displayed with lowsaturation, that is to say, almost in black and white, in accordancewith the elapsed time period of ten seconds.

A partial reading region 202 refers to a region in which an image(partial image) acquired through partial reading in the partial readingmode of the image capturing element is superimposed over an image(entire image) acquired through entire-pixel reading in the all pixelreading mode. An image corresponding to the partial reading region 202is frequently updated using images that are transmitted from the imagetransmission unit 103 with high frequency. Image processing for reducingthe saturation is not applied to this region. Therefore, by looking atthe entire image display part 201, a portion that has not been updatedsince pixels were last read can be visually confirmed.

A partial image display part 203 displays the image corresponding to thepartial reading region 202 in an enlarged manner. While the entire imagedisplay part 201 and the partial image display part 203 are displayed inthe same window in the present example, they may alternatively bedisplayed separately in different windows or on different externalapparatuses. Furthermore, there may be a plurality of partial readingregions 202, and a plurality of partial image display parts 203corresponding to the plurality of partial reading regions 202.

A method for setting the image capturing instruction parameter and amethod for superimposing an image will now be described in more detail.

The image capturing instruction parameter is set by the setting unit151. More specifically, the image capturing instruction parameter isset, for example, by a user via an input device such as a mouse and akeyboard.

First, the user designates a region targeted for partial reading bydesignating a diagonal of a rectangle on an entire image via a dragoperation. That is to say, a diagonal of the partial reading region 202is designated on the entire image display part 201. Subsequently, a skipinterval for pixels on the image capturing element is designated. FIG. 3shows an example of a user interface 300 for designating the skipinterval.

In FIG. 3, a radio button 301 is a control element for selecting thesetting in which pixels are not skipped. A radio button 302 is a controlelement for selecting the setting in which vertical columns andhorizontal rows of pixels are each read at a density of ½. In this case,the number of read pixels is approximately ¼ of the number of pixelsread in the case where pixels are not skipped. A radio button 303 is acontrol element for selecting the setting in which vertical columns andhorizontal rows of pixels are each read at a density of ¼. A radiobutton 304 is a control element with which an arbitrary skip intervalcan be set by inputting an arbitrary numeric value to a text field 305.

One of the radio buttons 301 to 304 can be selected, and FIG. 3 showsthe state where the radio button 302 is selected.

Furthermore, an arbitrary reading frequency can be set by inputting anarbitrary numeric value to a text field 306.

By pressing an OK button 307, the selected or designated parameter isdesignated as the skip interval. The designated skip interval iscancelled by pressing a cancel button 308.

The setting unit 151 may automatically set the image capturinginstruction parameter in accordance with the result of output from anexternal sensor (not shown in the drawings) and an image analysisprocessing unit (not shown in the drawings). For example, the imageanalysis processing unit detects a moving object by analyzing an imagestored in the storage unit 154. The setting unit 151 acquires theposition and the size of the moving object detected via moving-objectdetection, and determines a region including the moving object, a skipinterval corresponding to the size of the moving object, and a readingfrequency corresponding to the speed of the moving object. Then, thesetting unit 151 automatically sets the region including the movingobject, the skip interval, and the reading frequency as the imagecapturing instruction parameter.

The setting unit 151 further transmits the set image capturinginstruction parameter to the image capturing control unit 101 inaccordance with a predetermined protocol. FIG. 4 shows an example of aprotocol expressed as a text file.

More specifically, FIG. 4 shows an example of an image capturinginstruction parameter for the case where there are two partial readingregions. This parameter indicates that a first partial reading region401 has upper-left coordinates (x, y) of (200, 200), a horizontal widthof 800, a vertical height of 600, a skip interval of ½, and a readingfrequency of ten per second. This parameter also indicates that a secondpartial reading region 402 has upper-left coordinates (x, y) of (1300,600), a horizontal width of 200, a vertical height of 150, and a readingfrequency of 30 per second, and that pixels are not skipped in thesecond partial reading region 402.

Below is a detailed description of the operations of the imageprocessing unit 153 with reference to a flowchart of FIG. 5. The imageprocessing unit 153 is a computer, and executes processing shown in FIG.5 by executing a program read from a memory (not shown in the drawings).The flowchart of FIG. 5 represents a part of the program executed by theimage processing unit 153, i.e. the computer. The memory is a storagemedium storing the program in such a manner that the image processingunit 153, i.e. the computer can read the program.

In step S501, the image processing unit 153 determines whether or not anold image is stored in the storage unit 154. It should be noted that theold image denotes an old superimposition image that the image processingunit 153 stored in the storage unit 154. The angle of view of this oldimage matches the angle of view used in the case where the imagecapturing element performs all-pixel reading. It should be noted,however, that the resolution of the old image does not necessarily matchthe resolution used in the case where the image capturing elementperforms all-pixel reading. For example, in the case where the imagecapturing element has a horizontal resolution of 2000 pixels and avertical resolution of 1000 pixels, the old image may have a horizontalresolution of 2000 pixels and a vertical resolution of 1000 pixels, ormay have a horizontal resolution of 400 pixels and a vertical resolutionof 200 pixels.

If the old image is stored (the YES branch of step S501), the imageprocessing unit 153 proceeds to step S502 and reads the old image andpixel update time information stored in the storage unit 154. This pixelupdate time information shows the times when pixels of the old imagestored in the storage unit 154 were updated. On the other hand, if theold image is not stored (the NO branch of step S501), the imageprocessing unit 153 proceeds to step S503 and reads a default image thathas been prepared in advance instead of the old image. The default imageis, for example, an image in which all pixels are made of a singlecolor. This default image is also stored in the storage unit 154.

In step S504, the image processing unit 153 receives an image, an imagecapturing execution parameter, and an image generation time from theimage reception unit 152. The image received here will hereafter bereferred to as a latest image.

In step S505, the image processing unit 153 generates a superimpositionimage by superimposing the latest image over the old image such that theangle of view of the latest image matches the angle of view of the oldimage. The angle of view is calculated based on the resolution used inthe case where the image capturing element performs all-pixel reading,on the resolution of the old image, and on the image capturing executionparameter of the latest image. The image capturing execution parameterof the latest image includes a region of the latest image on the imagecapturing element. At the same time, the pixel update time informationis updated. The pixel update times of pixels that are included in theold image or the default image read from the storage unit 154 and havebeen updated using the latest image are updated to the image generationtime of the latest image.

In step S506, the image processing unit 153 stores the resultantsuperimposition image and pixel update time information in the storageunit 154.

In step S507, the image processing unit 153 determines to apply, to thepixels in the superimposition image, at least one of processing in stepsS508, S509 and S510 that enables visual distinction. This determinationmay be made based on a preset user designation, or may be madeautomatically based on the image capturing execution parameter receivedfrom the image reception unit 152.

In step S508, the image processing unit 153 applies processing forenabling visual distinction to the pixels in the superimposition imagein accordance with the reading frequency for image reading.

The following describes an example in which the processing for enablingvisual distinction is executed in accordance with the reading frequencyfor image reading with reference to FIGS. 6A and 6B. In this example, asshown in FIG. 6A, the effect of image processing is more intense for arange with a lower reading frequency. For example, processing isexecuted such that the lower the reading frequency for a range, thedarker the range. The reading frequency may be calculated by countingthe number of times each pixel is updated in the image processing unit153. The reading frequency may be included in the image capturingexecution parameter passed from the image transmission unit 103 to theimage reception unit 152. It should be noted that the reading frequencyand the intensity of the effect of image processing may satisfy anyrelationship. For example, image processing may be executed only if thereading frequency is smaller than a certain preset threshold.

In FIG. 6B, an entirety of a screen is read at a rate of once every 3seconds, a region 701 is read at a rate of 10 times per second, and aregion 702 is read at a rate of 30 times per second. Here, the effect ofimage processing is more intense for a region with a lower readingfrequency. For example, as the reading frequency for the region 702 ishigh, image processing is not applied thereto. Image processing isapplied to the region 701 so as to enable visual perception of the lowreading frequency therefor compared to the reading frequency for theregion 702. The effect of image processing for a region other than theregions 701 and 702 is more intense than the effect of image processingfor the region 701 so as to enable visual perception of the low readingfrequency therefor compared to the reading frequency for the region 701.

In step S509, the image processing unit 153 calculates a post-pixelupdate elapsed period for each pixel in the superimposition image. Apost-pixel update elapsed period refers to a difference between an imagegeneration time of the latest image and a pixel update time of thesuperimposition image. Subsequently, processing for enabling visualdistinction is executed in accordance with the post-pixel update elapsedperiod.

The following describes an example in which the processing for enablingvisual distinction is executed in accordance with the post-pixel updateelapsed period with reference to FIGS. 7A and 7B. In this example, asshown in FIG. 7A, the effect of image processing is more intense for arange with a longer post-pixel update elapsed period. It should be notedthat the post-pixel update elapsed period and the intensity of theeffect of image processing may satisfy any relationship. For example,image processing may be executed only if the post-pixel update elapsedperiod is longer than a certain preset threshold.

FIG. 7B shows images acquired after the image processing of the imageprocessing unit 153 in the case where all-pixel reading is performedfrom time t=0 to time t=6 and partial reading is performed with respectto the central portion of the screen at time t=7 onward.

From time t=0 to time t=6, all of the pixels in the image are updated.Therefore, the post-pixel update elapsed periods of all of the pixels inthe image are zero. At time t=7 onward, only pixels belonging to thearea targeted for partial reading are updated. Therefore, in 703, 704and 705 of FIG. 7B, while the post-pixel update elapsed periods of thepixels belonging to the partial reading region 202 at the centralportion of the screen are 0, the post-pixel update elapsed periods ofpixels belonging to other regions gradually increase. As the post-pixelupdate elapsed periods increase, the intensity of the effect of imageprocessing increases. For example, from time t=0 to time t=6, i.e. whenall pixels are updated, image processing is not executed. At time t=7,as the partial reading region is updated and a region other than thepartial reading region is not updated, image processing is executed soas to enable visual perception of the state where the region other thanthe partial reading region is not updated when the partial readingregion is updated.

Furthermore, at time t=8, the partial reading region is updated, and theregion other than the partial reading region is not updated. Therefore,further image processing is applied to the image to which imageprocessing was applied at time t=7, so as to enable visual perception ofthe state where the region other than the partial reading region has notbeen updated since before time t=7 when the partial reading region isupdated. Image processing may be applied to the entire image at time t=6such that the effect thereof is more intense than the effect of imageprocessing applied at time t=7.

In step S510, the image processing unit 153 applies processing forenabling visual distinction to the pixels in the superimposition imagein accordance with the skip interval for image reading.

The following describes an example in which the processing for enablingvisual distinction is executed in accordance with the skip interval forimage reading with reference to FIGS. 8A and 8B. In this example, asshown in FIG. 8A, the effect of image processing is more intense for arange that includes pixels for which reading is skipped at a higherrate. It should be noted that the skip interval and the intensity of theeffect of image processing may satisfy any relationship. For example,image processing may be executed only if the skip is performed.

In FIG. 8B, the entirety of the screen is read at a skip interval of ⅛,an area 1101 is read at a skip interval of ½, and a region 1102 is readwith no skip. The effect of image processing is more intense for a rangethat includes pixels for which reading is skipped at a higher rate. Thatis to say, image processing is not applied to the region 1102, and imageprocessing is applied to the area 1101 so as to enable visual perceptionof the low resolution thereof compared to the resolution of the region1102. Image processing is applied to a region other than the regions1101 and 1102 so as to enable visual perception of the low resolutionthereof compared to the resolution of the region 1101.

There are various examples of image processing in step S508, S509 orS510 that enables visual distinction. Such examples include: processingfor reducing saturation of the image, that is to say, processing formaking a color image close to a black-and-white image; shadingprocessing using uniform patterns such as dots and oblique lines;processing for reducing contrast of the image; processing for reducingbrightness of the image; airbrushing processing; and mosaic processing.

The processing for enabling visual distinction is not limited to theabove examples, and may be any image processing that enables visualdistinction among the reading frequencies for image reading, the skipintervals for image reading, or the post-pixel update elapsed periods.Such image processing may be, for example, processing for changing thecolor or thickness of a frame corresponding to a reading region in animage, processing for displaying an icon, and processing for displayinga predetermined image (a numeric value and the like).

Furthermore, the processing for enabling visual distinction may beexecuted in a stepwise manner in accordance with whether or not thereading frequency for an image is high or low. Similarly, the processingfor enabling visual distinction may be executed in a stepwise manner inaccordance with whether or not the post-pixel update elapsed period islong or short. Similarly, the processing for enabling visual distinctionmay be executed in a stepwise manner in accordance with whether or notthe skip interval is large or small.

For example, in the case where the image capturing unit can switchbetween a first reading frequency (for example, 10 fps) and a secondreading frequency (for example, 30 fps), processing may be executed soas to enable visual distinction between a first image that is read inthe first reading mode at 10 fps and a second image that is read in thesecond reading mode at 30 fps. In this case, the first image and thesecond image may be displayed in contrast to each other on the samescreen, or may be displayed separately on different display apparatuses.Such display control can of course be applied also to the aforementionedall-pixel reading mode (first reading mode) and partial reading mode(second reading mode). That is to say, in the concept of the presentinvention, it is sufficient to realize processing for enabling visualdistinction among images that are read in multiple types of readingmodes of the image capturing unit, and the methods for outputting suchimages are not limited to the examples of display described above withreference to FIGS. 7A to 8B.

As described above, when displaying images read from an image capturingelement that can change an image reading method, the present embodimentmakes it possible to execute processing for enabling visual distinctionamong the reading frequencies for image reading, the skip intervals forimage reading, or time periods that have elapsed since the last imageupdate.

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions recorded on a storage medium (e.g., non-transitorycomputer-readable storage medium) to perform the functions of one ormore of the above-described embodiment(s) of the present invention, andby a method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiment(s). The computer may comprise one or more ofa central processing unit (CPU), micro processing unit (MPU), or othercircuitry, and may include a network of separate computers or separatecomputer processors. The computer executable instructions may beprovided to the computer, for example, from a network or the storagemedium. The storage medium may include, for example, one or more of ahard disk, a random-access memory (RAM), a read only memory (ROM), astorage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2013-007844, filed Jan. 18, 2013, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image processing apparatus for processingcaptured image data that has been read from an image capturing unit, theapparatus comprising: an input unit configured to input captured imagedata that has been read from the image capturing unit in accordance witha reading mode; and a processing unit configured to process the capturedimage data input by the input unit so as to enable identification of thereading mode used in reading the captured image data from the imagecapturing unit.
 2. The apparatus according to claim 1, wherein thereading mode includes a reading frequency, and the processing unitprocesses the captured image data input by the input unit so as toenable identification of the reading frequency at which the capturedimage data has been read from the image capturing unit.
 3. The apparatusaccording to claim 1, wherein the processing unit updates image datastored in a storage unit using the captured image data input by theinput unit, and executes processing so as to enable identification ofthe reading mode used in reading the captured image data from the imagecapturing unit and of a time period that has elapsed since the update ofthe image data stored in the storage unit using the captured image datainput by the input unit.
 4. The apparatus according to claim 1, whereinthe processing unit updates image data stored in a storage unit usingcaptured image data that has been read from the image capturing unit inaccordance with different reading modes for a first region and a secondregion, and processes the image data stored in the storage unit so as toenable identification of reading of the captured image data inaccordance with the different reading modes for the first region and thesecond region.
 5. The apparatus according to claim 1, wherein the inputunit inputs captured image data that has been read from the imagecapturing unit through thinned-out reading in accordance with a readingmode, and the processing unit processes the captured image data input bythe input unit so as to enable identification of the reading mode usedin reading the captured image data from the image capturing unit throughthe thinned-out reading.
 6. The apparatus according to claim 1, whereinthe reading mode includes at least one of a bit depth of the imagecapturing element and a number of bands of the image capturing element.7. The apparatus according to claim 1, wherein the processing unitapplies at least one of processing for reducing saturation of an image,shading processing, processing for reducing contrast of an image,processing for reducing brightness of an image, airbrushing processing,and mosaic processing to the captured image data input by the input unitso as to enable identification of the reading mode used in reading thecaptured image data from the image capturing unit.
 8. The apparatusaccording to claim 1, wherein the processing unit applies at least oneof processing for changing a color of a frame corresponding to a readingregion in an image, processing for changing a thickness of the frame,processing for displaying an icon, and processing for displaying a valueto the captured image data input by the input unit so as to enableidentification of the reading mode used in reading the captured imagedata from the image capturing unit.
 9. An image processing method usedin an image processing apparatus for processing captured image data thathas been read from an image capturing unit, the method comprising thesteps of: inputting captured image data that has been read from theimage capturing unit in accordance with a reading mode; and processingthe input captured image data so as to enable identification of thereading mode used in reading the captured image data from the imagecapturing unit.
 10. The method according to claim 9, wherein the readingmode includes a reading frequency, and in the processing step, the inputcaptured image data is processed so as to enable identification of thereading frequency at which the captured image data has been read fromthe image capturing unit.
 11. The method according to claim 9, whereinin the processing step, image data stored in a storage unit is updatedusing the input captured image data, and processing is executed so as toenable identification of the reading mode used in reading the capturedimage data from the image capturing unit and of a time period that haselapsed since the update of the image data stored in the storage unitusing the input captured image data.
 12. The method according to claim9, wherein in the processing step, image data stored in a storage unitis updated using captured image data that has been read from the imagecapturing unit in accordance with different reading modes for a firstregion and a second region, and the image data stored in the storageunit is processed so as to enable identification of reading of thecaptured image data in accordance with the different reading modes forthe first region and the second region.
 13. The method according toclaim 9, wherein in the inputting step, captured image data that hasbeen read from the image capturing unit through thinned-out reading inaccordance with a reading mode is input, and in the processing step, theinput captured image data is processed so as to enable identification ofthe reading mode used in reading the captured image data from the imagecapturing unit through the thinned-out reading.
 14. A storage mediumhaving stored therein a computer program for processing captured imagedata that has been read from an image capturing unit, the programcomprising the steps of: inputting captured image data that has beenread from the image capturing unit in accordance with a reading mode;and processing the input captured image data so as to enableidentification of the reading mode used in reading the captured imagedata from the image capturing unit.
 15. The medium according to claim14, wherein the reading mode includes a reading frequency, and in theprocessing step, the input captured image data is processed so as toenable identification of the reading frequency at which the capturedimage data has been read from the image capturing unit.
 16. The mediumaccording to claim 14, wherein in the processing step, image data storedin a storage unit is updated using the input captured image data, andprocessing is executed so as to enable identification of the readingmode used in reading the captured image data from the image capturingunit and of a time period that has elapsed since the update of the imagedata stored in the storage unit using the input captured image data. 17.The medium according to claim 14, wherein in the processing step, imagedata stored in a storage unit is updated using captured image data thathas been read from the image capturing unit in accordance with differentreading modes for a first region and a second region, and the image datastored in the storage unit is processed so as to enable identificationof reading of the captured image data in accordance with the differentreading modes for the first region and the second region.
 18. The mediumaccording to claim 14, wherein in the inputting step, captured imagedata that has been read from the image capturing unit throughthinned-out reading in accordance with a reading mode is input, and inthe processing step, the input captured image data is processed so as toenable identification of the reading mode used in reading the capturedimage data from the image capturing unit through the thinned-outreading.